servo: Merge #18826 - style: Fix invalidation collection for XBL when quirks...

servo: Merge #18826 - style: Fix invalidation collection for XBL when quirks modes don't match (from emilio:invalidation-xbl-stuff); r=heycam

Source-Repo: https://github.com/servo/servo
Source-Revision: 105c5d2a0692c6e09320c5d967b43f879c3cd00d

--HG--
extra : subtree_source : https%3A//hg.mozilla.org/projects/converted-servo-linear
extra : subtree_revision : dd1e8319dfe62a1b0793e8e323db174a1b311bd9